Concave closure seal

ABSTRACT

An apparatus forming a closure seal especially adapted for utilization wherein high internal pressures are to be contained within a cylindrical high pressure cell. The closure seal is formed of a concave inner cylinder which readily transforms the pressures exerted within the cell to lateral forces which are exerted between the concave closure seal and the cylinder walls of the cell.

[52] US. Cl. 220/46 P, 220/82 R [5 1] Int. Cl 865d 53/00 [58] Field ofSearch 220/46 P, 46 MS, 220/46 R, 82 R [56] References Cited UNITEDSTATES PATENTS 2,483,156 9/1949 Schmitz, Jr. 220/46 R 2,528,665 11/1950Peterson et a1. 220/46 MS 2,725,252 11/1955 Greer 220/46 R X 2,734,7622/1956 Aleck 220/46 R X 3,055,537 9/1962 Watts 220/46 R Unlted StatesPatent 1 1 [111 3,782,585

Rosenwald et al. Jan. 1, 1974 [541 CONCAVE CLOSURE SEAL 3,458,081 7/1969Sherman. 220/46 R 3,462,041 8/1969 Wilson [75] Inventors g fifg g 31'2"3,537,611 11/1970 Lohrengel 220 40 R x [73] Assignee: Cities Service OilCompany, Tulsa, FOREIGN PATENTS OR APPLICATIONS Okla 823,388 11/1959016m Britain 220/46 MS [22] Filed: Dec. 10, 1971 PrimaryExaminer--William T. Dixson, Jr. Assistant Examiner-James R. GarrettAtt0rney.]. Richard Geaman [5 7] ABSTRACT An apparatus forming a closureseal especially adapted for utilization wherein high internal pressuresare to be contained within a cylindrical high pressure cell. The closureseal is formed of a concave inner cylinder which readily transforms thepressures exerted within the cell to lateral forces which are exertedbetween the concave closure seal and the cylinder walls of the cell.

2 Claims, 3 Drawing Figures 1 CONCAVE CLOSURE SEAL BACKGROUND OF THEINVENTION The present invention relates to an apparatus for forming ahigh pressure seal. More particularly, the apparatus of the presentinvention provides a concave closure seal for utilization withcylindrical pressure cells.

High pressure seals inherently cause problems in which two or moremovingparts are difficult to seal due to differential expansion of the partsforming the seal. The differential expansion may be caused by pressurestresses, thermal stresses or any other means which tend to separate thetwo sealing surfaces from one another. Conventionally utilized seals,for example the O-ring, are often subject to failure when the clearancebetween two surfaces which are being separated by the seal increases,allowing the O-ring to extrude within the clearance and causing failureof the sealing mechanism.

What is required is a means for improving high pressure seals in orderto adequately provide for pressure stresses, thermal stresses and othersealing surface failure.

It is an object of the present invention to provide a means forimproving high pressure seals.

It is another object of the present invention to provide a closureclsoure seal for utilization with highpressure cylindrical cells.

With these and other objects in mind, the present invention may be morereadily understood through referral to the accompanying figures andfollowing discussion:

SUMMARY OF THE INVENTION The objects of the presnt invention areprovided through utilization of a concave closure seal which is appliedin conjunction with a high pressure cylindrical cell. In general, theconcave closure seal comprises an cylinder having an outside diameterapproximately that of the inside diameter of a cylindrical cell and .aconcave end which is exposed to the interior of the cylindrical cell. Inconjunction with the cylinder are means for sealing the outercircumferential surface of the cylinder from the inner circumferentialsurface of the cylindrical cell.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention may be morereadily understood through referral to the accompanying figures inwhich:

' FIG. 1 represents preferred embodiment of the concave closure seal ofthe present invention depicting a concave closure seal for utilizationin conjunction with a high pressure cylindrical cell;

FIG. 2 represents a preferred embodiment of the concave closure seal ofthe present-invention depicting its utilization as a piston sealingmeans; and

FIG. 3 represents a preferred embodiment of the concave closure seal ofthe present invention in which the seal is utilized as a glasscompression seal as, for example in a windowed pressure cell.

DETAILED DESCRIPTION OF THE INVENTION As disclosed, the presentinvention is a concave closure seal to be utilized in conjunction withhigh pressure cylindrical cells. The various embodiments that thepresent invention may comprise are more readily understood by referralto the accompanying Figures. In particular, in FIG. 1, a closure seal.is depicted wherein a cylindrical cell 14 is shown to have internallydisposed a cylinder 12. The cylinder 12 is illustrated having an outsidediameter 'approxiamtely that of the inside diameter of the cylindricalcell, 14 and having a concave end 18 which is exposed to the interior ofthe cylindrical cell 16. Means are provided for sealing the outercircumferential surface of the cylinder 12 from the innercircumferential surface of the cylindrical cell 14. In general, themeans for sealing these surfaces may be provided through the cylinder 12having one or more grooves 20 reamed about the outer circumferentialsurface between the end of the cylinder 12, as exposed to the interiorof the cylindrical cell 14, and the base of the concave surface 18. AnO-ring 22 is positioned within each of the recesses 20 of the cylinder12 to provide the sealing means wherein pressures exerted within thecylindrical cell are exposed to the concave surface 18 of the cylinder12 so as to exert lateral pressures outwardly from the concave surface18 in 'order to provide a sealing contact between the O-ring 22 and theinner circumferential wall of the cylindrical cell 14. In a preferredembodiment of the present invention, the closure seal is shown to have asampling port 30 and sampling tube 28 reamed through the cylinder 12such that samples in the liquid under pressure of the interior portionof the cylindrical cell 16 may be removed through the sampling tube 28and sampling port 30 to lend a versatility to the apparatus of thepresent inventron.

Still another embodiment of the present invention is readily depicted inFIG. 2 in which a piston sealing means utilizing the concave closureseal of the present invention is illustrated. In particular, thecylindrical cell 14 has the cylinder 12 shaped in the form of a pistonhaving a concave surface 18 on the inner surface of the piston andfurther comprising a second concave end 32 which is exposed to theinterior 38 of the cylindrical cell 14. Additional means for sealing theouter circumferential surface of the cylinder 12. from theinnercircumferential surface of the cylindrical cell 14 are also provided,comprising the cylinder having one or more grooves 34 reamed about itsouter circumferential surace between the end of the cylinder 12, asexposed to the interior of the cylindrical cell 14, and the base of theconcave surface 32. O-ring 36 is positioned within the groove 34 of thecylinder 12, as are the groove 20 and O-ring 22 on the opposite end ofthe cylinder to form the concave closure seal as already described inFIG. 1. If additional pressure differential is required, means forventing the volume between the seals at 22 and 36 can be provided. I

One may readily discern the utilization of the piston seal disclosed inFIG. 2 wherein the O-ring provides a dual service of allowingcompression thereof between the outer circumferential surface of thecylinder 12 and the inner circumferential surface of the cylindricalwall 14 and providing a lubricating means wherein the 0- rings 22 and 36form a contact between the walls of the cylinder and cylindrical cellsuch that the piston may laterally move within the cylindrical cell 14through disproportionate pressuring of concave surfaces 18 and 32,respectively.

FIG. 3 represents a preferred embodiment of the present invention inwhich the concave closure seal is utilized in combination with a glasscompression seal in order to provide a windowed cell arrangement. Thecylindrical cell 14 contains an end plug 40 turned within internalthreads 52 of the cylindrical cell 14 and meshing with the externalthreads 54 of the end plug 40. The cylinder 12 is positioned so as toface the concave surface 18 within the cylindrical cell 14 and isprovided with groove 20 and O-ring 22 so as to form the compressionseals required to seal the outer circumferential surface of thecylindrical cell 14. A further provision of the high pressure cell isthe placement of a site glass 44 between the end plug 40 and thecylinder 12, the site glass being ridigly retained by retaining screws42 passing within holes 48 of the end plug 40 and being internallymeshed with internal threads of holes 50 and two or more holes 50contained within the cylinder 12. The site glass 44 is further alignedwith holes 46 and 56 contained within the end plug 40 and cylinder 12,respectively. The holes are axially aligned so as to provide a view ofsite through the holes and the site glass 44 to the interior of thecylindrical cell 14, allowing for visual observation of the phaseequilibria or reactions occurring within the cylindrical cell 14. Ingeneral, the site glass will have a diameter greater than the diameterof the holes 46 and 56 of the end plug 40 and cylinder 12, respectively,and will be positioned so as to have its center aligned .with thecenters of the holes of the cylinder and end plug and rigidly positionedbetween the end plug 40 and the cylinder 12 by the retaining screws 42.

Therefore, the present invention provides a means wherein two surfacesmay experience the same or greater proximity as the internal pressure isincreased within a cyindrical cell. The particular design of thecylinder concave surface and materials of construction of the presentinvention may be based on any acceptable mathematical formula relatingthe strain at the outer radius of the cylinder to the internal pressure.For example, Lambs thick wall cylinder relation and Hooks Law may beutilized for the construction design of the apparatus of the presentinvention. This relationship is then utilized to determine the amount ofmaterial to be removed from the cylinder to obtain a desired expansioncoefficient for the pressures experienced within the cylindrical cell.For example, a fixed seal design should allow excess expansion of thecylinder while sliding seals, for example the piston shown in H6. 2,should utilize an expansion equal to that of the outer cylinder so as toprovide an exacting seal at all times for unobstructed movement of thepiston within the cylinder. Therfore, the apparatus of the presentinvention provides a means for improving high pressure seals whereinextended seal life and failsafe operation may be obtained.

While the invention has been described above with respect to certainembodiments thereof, it will be understood by those skilled in the artthat various changes and modifications may be made without departingfrom the spirit and scope of the invention as set forth herein.

Therefore, we claim:

1. A concave closure seal for utilization in conjunction with highpressure cylindrical cells comprising a cylindrical cell beinginternally threaded at an end, a cylinder having an outside diameterapproximately that of the inside diameter of the cylindrical cell andhaving a concave end which is exposed to the interior of the cylindricalcell, said cylinder having one or more grooves about its outercircumferential surface between that end of the cylinder exposed to theinterior of the cylindrical cell and the concave surface thereof, and anaxial opening in said cylinder having its center approximately coaxialwith the axis of said cylinder and a plurality of internally threadedholes situated approximately equidistant from the axis of said cylinderon the exterior end of the cylinder, an O-ring positioned within each ofthe grooves of the cylinder, an exterally threaded end plug threadedwithin the end of said internal threads of said cylindrical cell, saidend plug having an opening whose center is approximately co-axial withthe axis of said cylinder and a plurality of holes situatedapproximately equi-distant from the axis of said cylinder, said end plugholes traversing the entire structure of said end plug, and two or moreretaining screws passing through said end plug holes and caused to meshwith said internal threads of said holes in the exterior of saidcylinder.

2. The concave closure seal of claim 1 wherein said end plugadditionally includes a counterbore concentric with and having a radiuslarger than said end plug opening and less than the equi-distances ofsaid end plug holes from said axis of said cylinder, a site glass havinga diameter greater than the diameter of said opening of said cylinderand said opening of said end plug, and less than the diameter of saidcounterbore of said end plug, said site glass being positioned withinsaid counterbore of said end plug and between said end plug and saidcylinder so as to have its center approximately axially aligned with thecenters of said opening of said cylinder and said opening of said endplug.

1. A concave closure seal for utilization in conjunction with highpressure cylindrical cells comprising a cylindrical cell beinginternally threaded at an end, a cylinder having an outside diameterapproximately that of the inside diameter of the cylindrical cell andhaving a concave end which is exposed to the interior of the cylindricalcell, said cylinder having one or more grooves about it''s outercircumferential surface between that end of the cylinder exposed to theinterior of the cylindrical cell and the concave surface thereof, and anaxial opening in said cylinder having its center approximately coaxialwith the axis of said cylinder and a plurality of internally threadedholes situated approximately equidistant from the axis of said cylinderon the exterior end of the cylinder, an O-ring positioned within each ofthe grooves of the cylinder, an externally threaded end plug threadedwithin the end of said internal threads of said cylindrical cell, saidend plug having an opening whose center is approximately co-axial withthe axis of said cylinder and a plurality of holes situatedapproximately equi-distant from the axis of said cylinder, said end plugholes traversinG the entire structure of said end plug, and two or moreretaining screws passing through said end plug holes and caused to meshwith said internal threads of said holes in the exterior of saidcylinder.
 2. The concave closure seal of claim 1 wherein said end plugadditionally includes a counterbore concentric with and having a radiuslarger than said end plug opening and less than the equi-distances ofsaid end plug holes from said axis of said cylinder, a site glass havinga diameter greater than the diameter of said opening of said cylinderand said opening of said end plug, and less than the diameter of saidcounterbore of said end plug, said site glass being positioned withinsaid counterbore of said end plug and between said end plug and saidcylinder so as to have its center approximately axially aligned with thecenters of said opening of said cylinder and said opening of said endplug.